Downtown Denver’s skyscrapers are only minutes behind me as I take a right at a car parts shop in Commerce City, followed quickly by a left just before the 18,000-seat stadium that is home to the Colorado Rapids soccer team.

This 15,000-acre site where the U.S. Army made mustard gas during World War II was once on the Superfund list of high-priority hazardous-waste sites. Its transformation, completed in 2010, was no easy journey. But Tom Dougherty, a former regional director of the National Wildlife Federation, says it’s something of a victory that few now remember the decades of environmental debates, legislative wrangling and literal and figurative heavy lifting that went into creating the refuge.

The buildings that housed military chemical factories have been razed. Contaminated soil has been moved to two onsite landfills, still maintained and monitored by the Army. The U.S. Fish & Wildlife Service has restored native grasses and flowers but left trees planted by the homesteaders who settled the area before the Army moved in following Pearl Harbor.

With memories of World War I’s mustard gas attacks still fresh, the U.S. and other governments thought it prudent to stockpile chemical weapons during World War II, though the U.S. did not use such weapons in that conflict. Souvenirs of the manufacturing and stockpiling can be seen at the visitor’s center near the refuge entrance, including a yellow-and-black warning sign that features a picture of a face mask.

Outside today, the warning signs along the roads and hiking paths also are yellow and black. But they show leaping deer.

Hawks, coyotes, burrowing owls, prairie dogs and badgers live in the Rocky Mountain Arsenal, which is open year-round and charges no admission fee. The refuge has more than 330 species of mammals, birds, reptiles, amphibians and fish. In 2007, a herd of bison was introduced.

In the winter, bald eagles roost in the refuge. The national bird is something of a mascot. An Army contractor working to clean up hazardous waste spotted a roosting pair at Rocky Mountain Arsenal in 1986. The sighting spurred efforts to create the refuge.

Colder weather also attracts photographers eager to capture deer during rutting season, and snowshoers. (Cross-country skiing is not permitted in the park.)

Change at the site has been gradual, with tracts cleaned up, declared safe by the U.S. Environmental Protection Agency and handed over to the Fish & Wildlife Service in stages. The Wildlife Drive is the park’s newest attraction. I got a preview with Susan Drobniak of Fish & Wildlife at the wheel, leaving me free to spot wildlife and take pictures.

Drobniak worked as an Army contractor spokeswoman during the cleanup for 12 years. She switched to Fish & Wildlife two and a half years ago, and now marvels at the respite for the senses the area offers city dwellers.

“It’s very beautiful,” she said. “And it has a lot of sound. We’ll hear red-wing blackbirds singing. You’ll hear the deer walking through the tall grasses. You’ll hear bison grunting. You’ll hear all the different calls of the prairie dogs.”

I also heard the odd plane, landing at or taking off from Denver International Airport, which borders the park to the east. Drobniak says visitors, some from foreign countries, with a long airport layover have been known to take a taxi to the refuge.

The refuge also is bordered by low-income neighborhoods that are home to many Hispanic and black residents. Dougherty, of the National Wildlife Federation, sees that as an opportunity to connect with communities that don’t often get to visit wild areas.

“It doesn’t serve me well to just say, ‘Here it is, come enjoy it,’ because the people who really need it may not come,” he said.

Drobniak said outreach programs include bringing in children from nearby schools, which can apply for grants to cover transportation costs.

Dougherty, meanwhile, brings his grandchildren.

“And they really enjoy it,” he said. “It’s very heartening to me, to have been involved in this process.”